JP2018123217A - Chemical heat storage body granulated article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chemical heat storage body granulated article having further enhanced reaction durability and high in strength and heat storage density.SOLUTION: A chemical heat storage body granulated article is constituted to be particulate by a material capable of chemically storing heat, and has a chemical heat storage particle having specific surface area of 2 m/g to 203 m/g and a porous coating film formed on a surface of the chemical heat storage particle. Circularity R of the chemical heat storage body granulated article is 0.8 or more. The circularity R is defined by the following formula. R=4πS/L, wherein S:projected area of the chemical heat storage body granulated article. L:length of contour line of the chemical heat storage body granulated article.SELECTED DRAWING: None

Description

  The present invention relates to a granulated chemical heat storage body formed in a granular form.

  The heat storage technology using the physicochemical change of the material is roughly classified into three systems of sensible heat storage, latent heat storage, and chemical heat storage depending on the physicochemical phenomenon used.

  The sensible heat storage system is a heat storage system that utilizes temperature changes of materials. For example, heat is stored in warm water by heating cold water to warm water. The latent heat storage system is a heat storage system that utilizes the phase change of the material. For example, by freezing water into ice, heat (cold heat) is stored in the ice. The chemical heat storage system is a heat storage system that uses chemical changes (chemical reaction heat) of materials. For example, heat is stored in calcium oxide when calcium hydroxide is heated and chemically changed to calcium oxide. The stored heat is released when calcium oxide chemically changes to calcium hydroxide.

  As an advantage of the chemical heat storage system, a heat storage state can be maintained for a relatively long period of time in an environment where the heat storage material does not deteriorate or decompose. For example, calcium oxide can maintain its heat storage state at room temperature for a long period of time if it is in an atmosphere free from water vapor or carbonic acid. Further, the chemical heat storage method has an advantage that the energy density (heat storage density) at which heat can be stored is higher than other heat storage methods.

The following conditions can be shown as conditions required for materials that can be used for chemical heat storage (hereinafter referred to as chemical heat storage materials).
A. B. Cause reversible endothermic reaction. C. No by-product is produced or very little if any. High reaction durability (chemical and mechanical durability due to repeated main reactions) High reaction activity and high heat storage performance (heat storage density)

  By satisfying the condition A, the chemical heat storage material can be used repeatedly. By satisfying Condition B, it is possible to prevent the by-product from adversely affecting the main reaction (endothermic reaction), thereby prolonging the life (use limit) of the chemical heat storage material. Condition C does not decrease the reactivity of the main reaction due to the generation of by-products as shown in condition B and the pulverization of the chemical heat storage material caused by the repeated volume change of the chemical heat storage material accompanying the main reaction. This is the condition. By satisfying Condition C, the heat storage performance of the chemical heat storage material can be maintained over a long period of time. Condition D is a condition necessary for enhancing the superiority of the chemical heat storage material. When the reaction activity is high, heat can be instantaneously supplied to the heat demand. Moreover, if the heat storage performance is high, the heat storage device using this chemical heat storage material can be made compact. Such chemical heat storage materials that satisfy the conditions A to D are still under development.

  Patent Document 1 discloses a chemical heat storage material obtained by coating the surface of chemical heat storage particles (calcium oxide (CaO) particles) having an average particle diameter of 1 to 1000 nm with hydrophobized nanosilica particles having a size of about 1 to 50 nm. A granulated product is disclosed. According to the chemical heat storage granule described in Patent Document 1, the chemical heat storage particles collapse due to the repetition of volume change associated with the main reaction (heat storage and release) due to the reinforcing effect of the nanosilica particles coated with the chemical heat storage particles. (Micronization) is suppressed. Thereby, reaction durability improves.

  Patent Document 2 discloses a chemical heat storage granule formed by mixing and baking a powdery chemical heat storage material, a clay mineral, and a structural strength improving material. According to Patent Literature 2, a powdered chemical heat storage material is dispersed and held in the skeleton of the clay mineral and the structural strength improving material. For this reason, a gap is formed between the chemical heat storage materials, and the formation of such a gap suppresses rubbing of the chemical heat storage materials due to repeated volume changes accompanying the heat storage and release of the chemical heat storage materials and pulverization associated therewith. Therefore, the reaction durability is improved. In addition, due to the gap, a reaction product / reaction product introduction / discharge path associated with heat storage and heat dissipation can be sufficiently secured, and thus inhibition of such movement (diffusion) can be suppressed.

  Patent Document 3 discloses a chemical heat storage body granulated product obtained by supporting a chemical heat storage material on a porous body formed by heating a resin. According to Patent Document 3, it is possible to prevent the chemical heat storage material from collapsing and agglomerating due to repeated volume changes accompanying heat storage and release of the chemical heat storage material, and to improve reaction durability.

Special table 2014-514135 gazette Japanese Patent No. 5297669 JP 2011-162746 A

(Problems to be solved by the invention)
Generally, the chemical heat storage material granulated material which is a granular chemical heat storage material is formed into a columnar shape or a pellet shape by, for example, extrusion molding. When the shape of the chemical heat storage material granule is a cylindrical shape, a pellet shape, or a flat shape, corners and edges exist on the surface of the chemical heat storage material granulation material. In addition, when there are corners and edges on the surface of the chemical heat storage body granulated material, or when a large number of convex portions are formed on the surface of the chemical heat storage body granulated material, the chemical heat storage body granulation accompanying the main reaction A contact load (stress) concentrates on the corners, ends, or protrusions when adjacent chemical heat storage granulations come into contact with each other due to volume expansion / contraction of the object. If a contact load concentration part exists, the part is chipped or cracked. When such chipping or cracking occurs, the pulverization of the chemical heat storage granule is promoted. When the pulverization of the chemical heat storage material granulated material is promoted, the reaction durability decreases.

  An object of this invention is to provide the chemical heat storage body granulated material by which reaction durability is further improved, and also intensity | strength and heat storage performance are high.

The present invention is configured by a material capable of storing chemical heat in the form of particles, and has a specific surface area of 2 m ² / g or more and 203 m ² / g or less, and a porous shape formed on the surface of the chemical heat storage particles. A chemical heat storage body granulated product having a circularity R of 0.8 or more. Here, the circularity R is defined by the following equation.
R = 4πS / L ²
S: Projected area of granulated product of chemical heat storage material L: Length of contour line of granulated product of chemical heat storage material

  In this case, the chemical heat storage particles may contain calcium or magnesium. In particular, the chemical heat storage particles may be a particulate material that chemically changes to calcium oxide or magnesium oxide during heat storage and chemically changes to calcium hydroxide or magnesium hydroxide during heat dissipation.

  The coating film may be formed of a compound containing at least one selected from the group consisting of silicon, titanium, aluminum, and zirconium. In this case, the coating film may be formed of at least one selected from the group consisting of silica particles, titania particles, alumina particles, zirconia particles, aluminum nitride particles, and silicon carbide particles. More preferably, the coating film may be formed of at least one selected from the group consisting of silica particles, titania particles, alumina particles, and zirconia particles.

According to the present invention, since the circularity R of the chemical heat storage body granulated product is 0.8 or more, the reaction durability can be enhanced. Moreover, since the porous coating film is formed on the surface of the chemical heat storage particles, the strength can be increased. Furthermore, since the specific surface area of the chemical heat storage particles is 2 m ² / g or more and 203 m ² / g or less, heat storage performance can be enhanced while maintaining strength and reaction durability. Therefore, according to the present invention, it is possible to provide a chemical heat storage body granulated product having high reaction durability, strength, and heat storage performance.

It is a SEM image of the chemical heat storage body granulated material which concerns on Example 1. FIG. It is a SEM image which shows the cross section of the chemical heat storage body granulated material which concerns on Example 1. FIG. It is a SEM image which shows the surface of the chemical heat storage body granulated material which concerns on Example 1. FIG. It is a SEM image of the chemical heat storage body granulated material which concerns on the comparative example 1. FIG. It is a SEM image of the chemical heat storage body granulated material which concerns on the comparative example 4. It is a SEM image which shows the surface of the chemical heat storage body granulated material which concerns on the comparative example 4. It is the schematic of the temperature rising apparatus used in order to measure temperature rising temperature.

  The chemical heat storage granule according to the present invention includes chemical heat storage particles and a coating film.

  The chemical heat storage particles are formed into particles by a material capable of storing chemical heat. The chemical heat storage particles may contain calcium or magnesium. When the chemical heat storage particles include calcium, the chemical heat storage particles chemically change to calcium oxide during heat storage and chemically change to calcium hydroxide during heat release. When the chemical heat storage particles contain magnesium, the chemical heat storage particles chemically change to magnesium oxide during heat storage and chemically change to magnesium hydroxide during heat dissipation.

When chemical heat storage particles chemically change to calcium oxide during heat storage and chemically change to calcium hydroxide during heat release, the chemical heat storage particles cause the main reaction (endothermic reaction or exothermic reaction) shown in the following chemical formula (1), Stores and dissipates heat.

When chemical heat storage particles chemically change to magnesium oxide during heat storage and chemically change to magnesium hydroxide during heat release, the chemical heat storage particles cause the main reaction (endothermic reaction or exothermic reaction) shown in the following chemical formula (2), Stores and dissipates heat.

  As shown in the chemical formula (1) (or chemical formula (2)), when calcium hydroxide (or magnesium hydroxide) is heated, calcium hydroxide (or magnesium hydroxide) is converted into calcium oxide (or magnesium oxide). Water vapor is generated with chemical changes. At this time, heat is stored in the chemical heat storage particles. Further, when calcium oxide (or magnesium oxide) is brought into contact with water vapor, calcium oxide (or magnesium oxide) chemically changes to calcium hydroxide (or magnesium hydroxide). At this time, the chemical heat storage particles dissipate heat. That is, the chemical heat storage particles store heat with a chemical change from hydroxide to oxide, and dissipate heat with a chemical change from oxide to hydroxide.

The chemical formula (1), varies depending literature value of the standard enthalpy of reaction [Delta] H ^○ _R in (2), for example, in the chemical formula (1) can be exemplified ΔH ^○ _R = 109kJ / mol, in the chemical formula (2), An example is ΔH ^o _R = 81.0 kJ / mol.

  The average particle size (volume average particle size) of the chemical heat storage particles is preferably 600 μm or more and 1500 μm or less. There exists a problem that the yield at the time of granulation falls that an average particle diameter is less than 600 micrometers. When the average particle diameter exceeds 1500 μm, there is a problem that the filling rate into the reaction tank of the chemical heat storage device decreases. The average particle diameter of the chemical heat storage particles can be adjusted during the granulation process of the chemical heat storage particles.

The specific surface area of the chemical heat storage particles is 2 m ² / g or more and 203 m ² / g or less. When the specific surface area is less than 2 m ² / g, a substance (for example, water vapor) necessary for the main reaction cannot be sufficiently taken into the chemical heat storage particles. For this reason, sufficient main reaction does not occur, thereby causing a decrease in heat storage performance. On the other hand, when the specific surface area exceeds 203 m ² / g, strength and reaction durability are deteriorated. Therefore, by adjusting the specific surface area of the chemical heat storage particles to the above range, the heat storage performance can be enhanced while maintaining a certain strength and reaction durability.

  The coating film is formed (coated) on the surface of the chemical heat storage particles in order to reinforce the chemical heat storage particles. The coating film may be a compound containing at least one selected from the group consisting of silicon (Si), titanium (Ti), aluminum (Al), and zirconium (Zr).

More preferably, the coating film includes a plurality of silica (SiO ₂ ) particles, a plurality of titania (TiO ₂ ) particles, a plurality of alumina (Al ₂ O ₃ ) particles, a plurality of zirconia (ZrO 2) particles, and a plurality of aluminum nitride ( It may be formed of at least one selected from the group consisting of AlN) particles and a plurality of silicon carbide (SiC) particles. More preferably, the coating film may be formed of at least one selected from the group consisting of a plurality of silica particles, a plurality of titania particles, a plurality of alumina particles, and a plurality of zirconia particles. These substances are chemically stable and do not react with the chemical heat storage particles even when exposed to a high temperature (for example, a maximum of 700 ° C.) during the heat storage and release of the chemical heat storage particles. Therefore, it can prevent that the reaction rate and reaction durability of a chemical thermal storage particle fall by generation | occurrence | production of a by-product. In addition, since these materials have high thermal conductivity, heat loss at the time of heat storage and release of chemical heat storage particles can be minimized by using these materials for the coating film.

  The coating film has a porous shape. When the coating film is a dense film, supply of a reaction gas (for example, water vapor) necessary for causing a main reaction to the chemical heat storage particles covered with the coating film is hindered. In this regard, when the coating film is formed in a porous shape by a plurality of silica particles, a plurality of titania particles, a plurality of alumina particles, a plurality of zirconia particles or the like (hereinafter referred to as coating particles), The reaction gas can be supplied to the chemical heat storage particles from the gap.

  The coating film can be formed, for example, by spraying the coating particles onto the chemical heat storage particles. In this case, for example, the coating film can be coated on the chemical heat storage particles using a fluidized bed apparatus or the like. The coating film can be formed, for example, by immersing and mixing a dispersion liquid in which coating particles are dispersed in a dispersion medium in chemical heat storage particles and volatilizing the dispersion medium (solvent) while stirring.

  The average particle size (volume average particle size) of the coating particles constituting the coating film is preferably 5 nm or more and 200 nm or less. When the average particle diameter of the coating particles is less than 5 nm, the gap between the coating particles becomes very small, and the reaction gas cannot be sufficiently supplied to the chemical heat storage particles. On the other hand, when the average particle diameter of the coating particles is larger than 200 nm, the gap between the coating particles becomes too large to obtain a sufficient reinforcing effect.

  The coating film should have water repellency. As shown in the chemical formulas (1) and (2), water vapor is generated by the endothermic reaction (heat storage) of the chemical heat storage particles. When the generated water vapor is cooled and condensed, the condensed water and the chemical heat storage body granulated material come into contact with each other, and a plurality of chemical heat storage body granulated materials are aggregated by liquid crosslinking. When an exothermic reaction is performed in this state, it becomes difficult to take in a reaction gas (for example, water vapor) from the agglomerated portion. On the other hand, if the coating film has water repellency, the chemical heat storage body granulated material repels dew condensation water, so that aggregation of the chemical heat storage body granulated material due to liquid crosslinking can be prevented. For this reason, the fall of a reaction rate and heat storage performance can be suppressed.

Moreover, the chemical heat storage body granulated product according to the present invention is formed so that the circularity R thereof is 0.8 or more. Here, the circularity R is defined by the following equation.
R = 4πS / L ²
In the above formula, S is the projected area of the chemical heat storage granule. Specifically, S is an area when the chemical heat storage material granulated material is projected in a predetermined direction. L is the length of the contour line of the chemical heat storage granule. Specifically, L is the length of the contour line representing the outer shape when the chemical heat storage body granulated product is projected in a predetermined direction. In the following, S may be simply referred to as a projected area, and L may be referred to as a contour length.

  When the shape of the chemical heat storage material granulated material is a shape other than the true sphere shape, the projected area S and the contour length L vary depending on the projection direction (or the posture of the chemical heat storage material granulated material viewed from the projection direction). In the present embodiment, as will be described later, the projected area S and the contour length L of the chemical heat storage material granule when the chemical heat storage material granule flowing in a certain direction is viewed from a direction perpendicular to the flow direction. The circularity is derived from the projection area S and the contour length L thus obtained. Therefore, the projected area S and the contour length L are the projected area and the contour length of the chemical heat storage granule when the chemical heat storage granule flowing along the predetermined flow is viewed from the direction perpendicular to the flow. Can be said. Moreover, in the Example mentioned later, from the projection area S and outline length L obtained by the above-mentioned method about the chemical heat storage body granule of the substantially same shape (for example, 1000 pieces) manufactured through a fixed manufacturing process. The circularity is derived, and the arithmetic average of the derived circularities is defined as the circularity R of the chemical heat storage granule. The posture in which a plurality of chemical heat storage body granulations flow along a predetermined flow varies. Therefore, it can be said that the arithmetic average value of the plurality of circularities is an arithmetic average value of the circularity obtained when the chemical heat storage body granulated material is projected from a plurality of different directions. That is, the circularity can be defined as an arithmetic average value of the circularity obtained from the projected area and the contour length when the chemical heat storage granule is projected from a plurality of different directions, for example, all directions.

  When the circularity R of the chemical heat storage material granulation is 0.8 or more, the shape of the chemical heat storage material granulation is close to a true sphere. By using the chemical heat storage material granulated material close to a true sphere, the packing density when a plurality of chemical heat storage material granulated materials are filled in the reaction tank of the chemical heat storage device can be increased. In this case, by using chemical regenerator granulates with various particle sizes, small chemical heat regenerator granules can be filled between large chemical heat regenerator granules. For this reason, the packing density can be further increased.

  Moreover, when the circularity R of the chemical heat storage material granulated product is high, particularly when the circularity R is 0.8 or more, the reaction durability can be sufficiently increased. The reason for this will be described below. When a main reaction shown in the above chemical formula (1) or (2), particularly an exothermic reaction, is caused in a state where a plurality of chemical heat storage body granules are filled in a reaction tank of a chemical heat storage device, water is generated from the oxide. The chemical heat storage granule expands in volume with the chemical change to oxide. When the individual chemical heat storage body granules expand in volume, adjacent chemical heat storage body granules are pressed against each other. Here, when the circularity of each chemical heat storage material granule is low, for example, when a corner or an end is formed in the chemical heat storage material granulation product, the contact load (stress) generated when pressing each other is not the end. Since it concentrates on the corners and corners, chipping and cracking occur at stress concentration sites (corners and edges). When chipping or cracking occurs in the chemical heat storage material granulated material, the chemical heat storage material granulated material is micronized. When the pulverization of the chemical heat storage material granulation proceeds by repeating the main reaction, the chemical heat storage material granulation aggregates. When the chemical heat storage body granules are aggregated in this way, it becomes difficult to take in the reaction gas from the aggregation site during the exothermic reaction, so that the reactivity and the heat storage performance are deteriorated. That is, when the circularity is low, the heat storage performance (heat storage density) of the chemical heat storage body granulated material cannot be maintained over a long period of time. That is, the reaction durability decreases.

  In this regard, when the circularity R of the chemical heat storage material granule is high, particularly when the circularity R is 0.8 or more, the shape of the chemical heat storage material granulation is close to a true sphere. There is almost no part or convex part. Therefore, the contact load (stress) produced by the adjacent chemical heat storage body granulations pressing against each other due to volume expansion during the main reaction (exothermic reaction) is dispersed. That is, when the circularity R is high, particularly when the circularity R is 0.8 or more, it is possible to effectively prevent the occurrence of a portion where the contact load (stress) is concentrated. Therefore, generation | occurrence | production of a chip | tip and a crack is suppressed effectively, and, thereby, pulverization of a chemical heat storage body granulated material is suppressed. As a result, even if it is used for a long time, the chemical heat storage material granulated material is prevented from being pulverized, and therefore the reaction durability is enhanced.

  In addition, in the above, although the advantage about circularity R of a chemical heat storage body granulated material having been 0.8 or more was described, the circularity degree of the chemical heat storage particle with which a chemical heat storage body granulated material is provided is also 0.8. That is good. When the circularity of the chemical heat storage particles is low, for example, when the circularity is less than 0.8, for example, when spraying the coating particles on the chemical heat storage particles from a predetermined direction to form a coating film, corners, protrusions, etc. There is a possibility that a part where the coating particles do not adhere is generated as a blind spot of the protruding part. For this reason, the site | part in which a coating film is not formed generate | occur | produces and micronization occurs from the part. As a result, reaction durability decreases. In this regard, when the degree of circularity of the chemical heat storage particles is high (0.8 or more), the coating film is uniformly formed on the surface of the chemical heat storage particles because the blind spot is small even when the coating particles are sprayed from a predetermined direction. Can be formed. That is, the coating property of the coating film can be improved by setting the circularity of the chemical heat storage particles to 0.8 or more. As a result, reaction durability can be improved.

Example 1
The chemical heat storage body granulated product according to Example 1 was manufactured through the following steps.
1. Core particle manufacturing process The core particle used as the core of chemical heat storage particle | grains was manufactured using the stir granulator GM-10 by Freund Sangyo Co., Ltd. In this case, first, 1000 g of calcium hydroxide powder (manufactured by Wako Pure Chemical Industries, Ltd., reagent special grade) is put into the stirring layer. Subsequently, a plurality of calcium hydroxide powders are bonded via a binder (polyvinyl alcohol) by spraying a 5 wt% polyvinyl alcohol aqueous solution (Wako Pure Chemical Industries, Ltd., degree of polymerization: about 500) onto the calcium hydroxide powder. Calcium hydroxide fine particles formed by bonding were prepared. By sieving the produced fine particles, core particles which are fine particles of calcium hydroxide having a particle size of 100 μm or more and 500 μm or less were produced.

2. Granulation process The core particles manufactured in the core particle manufacturing process were charged into a fluidized granulator CF-LABO manufactured by Freund Sangyo Co., Ltd. The device was then turned on to form a circulating stream of nuclear particles within the device. In addition, calcium hydroxide powder (manufactured by Wako Pure Chemical Industries, Ltd., special grade reagent) was quantitatively sprayed in the apparatus while quantitatively spraying the same binder liquid (polyvinyl alcohol aqueous solution) in the apparatus. Thereby, calcium hydroxide powder adheres to the circulating core particles little by little through the binder (polyvinyl alcohol), and the particle size gradually increases. Observe the inside of the device with a magnifying glass at any time and visually check the size of the granulated product. When the particle size of the granulated product grows to 600 μm or more and 1500 μm or less, the operation of the device is stopped and the granulation is finished. did. Thereafter, the granulated product was dried at 60 ° C. for 1 hour, and then the granulated product was sieved using a sieve having an opening of 600 μm to remove fine powder. Thereafter, the binder was degreased (removed) by baking in air at 750 ° C. for 15 minutes. In this way, spherical chemical heat storage particles were granulated.

3. Coating Step Silica fine particles having a volume average particle size of about 10 nm were prepared. Next, the prepared silica fine particles were dispersed in a PGM (propylene glycol monoethyl ether) liquid to prepare a silica-dispersed PGM liquid (silica concentration: 5 wt%). Then, a predetermined amount of the silica-dispersed PGM liquid was poured into a container containing the chemical heat storage particles granulated in the granulation step, and the PGM liquid was volatilized while stirring. Subsequently, it was dried at room temperature for 24 hours, and then fired in air at 500 ° C. for 10 minutes. Thereby, the coating layer formed of a plurality of silica fine particles (nanoparticles) was formed on the surface of the chemical heat storage particles. In Example 1, the weight ratio of the coating layer (silica) between the chemical heat storage particles and the silica-dispersed PGM liquid is 5 wt% with respect to the chemical heat storage body granulated product (chemical heat storage particles and coating layer). The mixing ratio was adjusted.

  The chemical heat storage body granulated product according to Example 1 was manufactured through the above steps (core particle manufacturing step, granulating step, coating step). FIG. 1A is an SEM image (magnification 50 times) of the chemical heat storage material granulation product according to Example 1. FIG. As shown in FIG. 1A, it can be seen that the shape of the chemical heat storage body granulated product according to Example 1 is almost spherical, and there are almost no corners, edges, or protrusions on the surface. FIG. 1B is an SEM image (magnification 1000 times) showing a cross section of the chemical heat storage body granulated product according to Example 1. As shown in FIG. 1B, the chemical heat storage body granulated product according to Example 1 includes chemical heat storage particles and a coating film formed on the surface of the chemical heat storage particles. Moreover, the film thickness of a coating film is very small compared with the diameter of a chemical heat storage particle. Moreover, FIG. 1C is a SEM image (400 times magnification) which shows the surface of the chemical heat storage body granulated material which concerns on Example 1. FIG. As shown to FIG. 1C, the surface of the chemical heat storage body granulated material which concerns on Example 1 is a substantially flat surface.

(Example 2)
Same as the chemical heat storage particles according to Example 1 by the agitation granulator GM-10 used in the core particle production step without carrying out the granulation using the fluidized granulator CF-LABO in the granulation step. Chemical heat storage particles of such a size were produced. Then, a coating film was formed on the surface of the produced chemical heat storage particles by the same method as in the coating step.

(Example 3)
The chemical regenerator granulated product according to Example 3 is subjected to the same steps as in Example 1 except that an aqueous polyvinyl alcohol solution having a concentration of 1 wt% is used as a binder liquid in the core particle production step and the granulation step. Manufactured.

Example 4
The chemical regenerator granulated product according to Example 4 is subjected to the same steps as in Example 1 except that a 7 wt% polyvinyl alcohol aqueous solution is used as a binder liquid in the core particle manufacturing step and the granulating step. Manufactured.

(Example 5)
The chemical heat storage body granulated product according to Example 5 is obtained through the same process as Example 1 except that a polyvinyl alcohol aqueous solution having a concentration of 9 wt% is used as a binder liquid in the core particle production process and the granulation process. Manufactured.

(Example 6)
In the coating step, the chemistry according to Example 6 was performed through the same steps as in Example 1 except that alumina fine particles having a volume average particle size of about 12 nm were used instead of silica fine particles having a volume average particle size of about 10 nm. A regenerator granule was produced.

(Example 7)
In the coating step, the chemistry according to Example 7 was performed through the same steps as in Example 1 except that zirconia fine particles with a volume average particle size of about 15 nm were used instead of silica fine particles with a volume average particle size of about 10 nm. A regenerator granule was produced.

(Example 8)
In the coating step, the chemical process according to Example 8 was performed through the same process as Example 1 except that titania particles having a volume average particle diameter of about 10 nm were used instead of silica particles having a volume average particle diameter of about 10 nm. A regenerator granule was produced.

Example 9
In the core particle production process and the granulation process, the same procedure as in Example 1 was performed, except that magnesium hydroxide powder (manufactured by Wako Pure Chemical Industries, Ltd.) was used instead of calcium hydroxide powder. A chemical heat storage granule according to Example 9 was produced.

(Example 10)
In the coating process, the mixing ratio between the chemical heat storage particles and the silica-dispersed PGM liquid so that the weight ratio of the coating layer is 0.5 wt% with respect to the chemical heat storage granule (chemical heat storage particles and coating layer). A chemical heat storage body granulated product according to Example 10 was produced through the same steps as in Example 1 except that was adjusted.

(Example 11)
In the coating process, the mixing ratio of the chemical heat storage particles and the silica-dispersed PGM liquid so that the weight ratio of the coating layer is 1.0 wt% with respect to the chemical heat storage granule (chemical heat storage particles and coating layer). A chemical heat storage body granulated product according to Example 11 was produced through the same steps as in Example 1 except that was adjusted.

(Example 12)
In the coating process, the mixing ratio of the chemical heat storage particles and the silica-dispersed PGM liquid is adjusted so that the weight ratio of the coating layer is 10 wt% with respect to the chemical heat storage granule (chemical heat storage particles and coating layer). A chemical heat storage body granulated product according to Example 12 was produced through the same steps as in Example 1 except that.

(Example 13)
In the coating process, the mixing ratio of the chemical heat storage particles and the silica-dispersed PGM liquid is adjusted so that the weight ratio of the coating layer is 20 wt% with respect to the chemical heat storage granule (chemical heat storage particles and coating layer). Except having done, the chemical heat storage body granulated material which concerns on Example 13 was manufactured through the process similar to Example 1. FIG.

(Comparative Example 1)
Instead of the core particle production process and granulation process described in Example 1, chemical heat storage particles were granulated by an extrusion process. In this extruding step, first, 1000 g of calcium hydroxide powder (manufactured by Wako Pure Chemical Industries, Ltd., reagent grade) is prepared, and this calcium hydroxide powder is used as a binder liquid with a concentration of 5 wt% polyvinyl alcohol aqueous solution (Wako The slurry was prepared by adding to and stirring with a Koyo Pure Chemical Industries, polymerization degree: about 500). And the produced slurry was injected | thrown-in to the extrusion granulator Multigran MG-55 type made from Dalton Co., Ltd., and the extrusion granulator was operated. Thereby, a cylindrical slurry-like solid having a diameter of 1 mm and a height of about 1 mm was obtained. The obtained slurry-like solid was dried at 60 ° C. for 1 hour and then sieved using a sieve having an opening of 600 μm to remove fine powder. Thereafter, baking was performed in air at 750 ° C. for 15 minutes to degrease the binder (polyvinyl alcohol). In this way, cylindrical chemical heat storage particles were granulated. Moreover, the coating process described in Example 1 was performed using the obtained chemical heat storage particles. Thereby, the coating layer which consists of silica microparticles (nanoparticles) is formed on the surface of the chemical heat storage particles.

  Through the above steps (extrusion step, coating step), a chemical heat storage body granulated product according to Comparative Example 1 was produced. FIG. 2 is an SEM image (magnification 50 times) of the chemical heat storage body granulated product according to Comparative Example 1. As can be seen from FIG. 2, the chemical heat storage body granulated product according to Comparative Example 1 has a cylindrical shape.

(Comparative Example 2)
In the core particle production process and the granulation process described in Example 1, a polyvinyl alcohol aqueous solution having a concentration of 0.5 wt% was used as the binder liquid, and the same process as in Example 1 was performed. The chemical heat storage body granulated material which concerns is manufactured.

(Comparative Example 3)
In the core particle production process and granulation process described in Example 1, a chemistry according to Comparative Example 3 was performed through the same process as Example 1 except that a polyvinyl alcohol aqueous solution having a concentration of 12 wt% was used as the binder liquid. A regenerator granule was produced.

(Comparative Example 4)
The core particle manufacturing process and the granulation process described in Example 1 were performed without performing the coating process described in Example 1, and the chemical heat storage body granulated product according to Comparative Example 4 was manufactured. FIG. 3A is an SEM image (magnification 50 times) of the chemical heat storage material granulated product according to Comparative Example 4. As shown in FIG. 3A, the shape of the chemical heat storage body granulated product according to Comparative Example 4 is slightly distorted than the chemical heat storage body granulated product according to Example 1 shown in FIG. Relatively close. FIG. 3B is an SEM image (400 times magnification) showing the surface of the chemical heat storage body granulated product according to Comparative Example 4. As shown to FIG. 3B, the surface of the chemical heat storage body granulated material which concerns on the comparative example 4 is rough because the coating film is not formed, and uneven | corrugated amount concerns on Example 1 shown to FIG. 1C. It can be seen that there are more irregularities on the surface of the granulated product of the chemical heat storage body.

(Measurement of circularity)
About the chemical heat storage body granulated material which concerns on each above-mentioned, circularity R was measured. The circularity R was measured using a powder image analyzer PITA-03 manufactured by Seishin Co., Ltd. In this case, first, the chemical regenerator granule to be measured is caused to flow in the flow cell so as to follow the flow of the fluid flowing in a predetermined direction inside the flow cell provided in the apparatus. When the chemical heat storage granule passes through the observation zone in the flow cell, an image of the chemical heat storage granule is taken from a direction perpendicular to the flow direction with a camera. By analyzing the photographed image, the projected area S and contour length L of the photographed chemical heat storage granule are measured, and the circularity is derived from the measured projected area S and contour length L. Such derivation of the circularity is performed on 1000 chemical heat storage body granulations for one example or comparative example, and the circularity of the 1000 chemical heat storage body granulations obtained is arithmetically averaged. Thus, the circularity R was determined.

(Measurement of specific surface area)
In the chemical heat storage granule according to each example, the specific surface area of the chemical heat storage particle before the coating film was formed (specific surface area of the chemical heat storage granule in Comparative Example 4) was measured. In this case, the specific surface area was measured by a gas adsorption BET method (adsorbed substance: nitrogen molecule) based on JIS R1626-1996 using a specific surface area measuring device NOVA2000 manufactured by Quantachrome. In the measurement, the measurement sample (chemical heat storage particles) was preliminarily calcined in air at 750 ° C. for 15 minutes to be chemically changed into an oxide. Further, this oxide was heat-treated at 250 ° C. under a reduced pressure of 0.7 Pa or less for 3 hours immediately before the measurement, and then the specific surface area was measured.

(Measurement of reaction rate)
The reaction rate of the main reaction of the chemical heat storage material granulated product according to each example was measured. The reaction rate was calculated based on an increase in weight when the exothermic chemical heat storage granule in an oxide state was subjected to an exothermic reaction (hydration reaction) and the exothermic reaction was saturated. A specific reaction rate measurement (calculation) procedure is as follows.

  First, about 15 mg of a sample of the chemical regenerator granule according to each example was collected in an alumina pan, and the collected sample was put into a TG-DTA apparatus (simultaneous differential thermal analysis apparatus) capable of introducing water vapor. . Next, the charged sample was heated to a predetermined temperature, and the sample was dehydrated to an oxide state. The temperature rise varies depending on the material of the chemical heat storage particles. When the chemical heat storage particles are calcium hydroxide, the temperature is raised to 500 ° C., and when the chemical heat storage particles are magnesium hydroxide, the temperature is raised to 400 ° C. It was. Thereafter, the temperature of the sample was lowered. When the temperature was lowered to 80 ° C., nitrogen gas containing water vapor was introduced into the apparatus. This initiates an exothermic reaction (hydration reaction) of the sample. As the exothermic reaction proceeds, the weight of the sample increases. The weight of the sample was measured sequentially, and the weight measurement was stopped when a sufficient time (for example, about 60 minutes) when the weight increase was saturated passed. Next, the difference between the weight of the sample in the initial stage (oxidized state) and the weight of the sample when the weight measurement was stopped was obtained as an actual weight increase. Then, the percentage of the ratio of the actual weight increase to the theoretical value of the weight increase when the 15 mg sample was completely hydrated was calculated as the reaction rate (%).

(Measurement of temperature rise)
About the chemical heat storage body granulated material which concerns on each example, temperature rising temperature (DELTA) T was measured. Here, the temperature rise ΔT is the initial temperature (temperature in the oxidized state) when the exothermic reaction shown in chemical formula (1) or chemical formula (2) is caused to occur in the chemical heat storage granule according to each example. ) And the maximum temperature reached. Therefore, when the initial temperature is 80 ° C. and the maximum temperature reached is 180 ° C., the temperature increase temperature ΔT is 100 ° C.

  In measuring the temperature rise, the temperature riser shown in FIG. 4 is used. As shown in FIG. 4, the temperature raising device 10 includes a reaction vessel 11, a steam generator 12, a vacuum pump 13, a mantle heater 14, a first pipe 15, a second pipe 16, and a third pipe 17. A first valve 18, a second valve 19, and a third valve 20.

  A certain amount of chemical regenerator granulated material according to each example is charged into the reaction vessel 11. A mantle heater 14 is disposed so as to surround the reaction vessel 11. The mantle heater 14 generates heat when power is supplied from a power source (not shown), and heats the reaction container 11 and the chemical regenerator granule charged into the reaction container 11.

  The water vapor generator 12 includes a case 121, a water storage tank 122, and a heater 123. The water tank 122 and the heater 123 are housed in the case 121. The water tank 121 is filled with water. The heater 122 is disposed around the water storage tank 121. The heater 122 generates heat when power is supplied from a power source (not shown), and heats the water storage tank 121 and water filled therein.

  The first pipe 15 is connected to the steam generator 12 at one end so as to communicate with the space in the case 121 of the steam generator 12. The second pipe 16 is connected to the reaction vessel 11 at one end so as to communicate with the space in the reaction vessel 11. The third pipe 17 is connected to the suction port of the vacuum pump 13 at one end thereof. And the other end of the 1st piping 15, the other end of the 2nd piping 16, and the other end of the 3rd piping 17 merge in the A point of FIG.

  A first valve 18 is interposed in the middle of the first piping 15, a second valve is interposed in the middle of the second piping 16, and a third valve is interposed in the middle of the third piping 17. These valves 18, 19, 0 are open / close valves.

  The procedure for measuring the temperature rise using the temperature raising device 1 having the above configuration is shown below.

(Procedure 1)
First, a certain amount of the chemical heat storage material granulated material is put into the reaction vessel 11. Next, the water storage tank 122 of the steam generator 12 is filled with a predetermined amount of water.

(Procedure 2)
Next, the first valve 18, the second valve 19, and the third valve 20 are all closed. Further, the heater 123 of the water vapor generator 12 is operated to heat the water in the water storage tank 122 to 50 ° C. As a result, water vapor having a temperature of 50 ° C. is generated.

(Procedure 3)
Subsequently, the second valve 19 and the third valve 20 are opened. Thereby, the internal space of the reaction vessel 11 is connected to the suction port of the vacuum pump 13 through the second pipe 16 and the third pipe 17. Further, the mantle heater 14 and the vacuum pump 13 are operated. The reaction vessel 11 is evacuated by the operation of the vacuum pump 13. Moreover, the chemical heat storage body granulated material in the reaction vessel 11 is heated to the target temperature (500 ° C. or 400 ° C.) by the operation of the mantle heater 14. An endothermic reaction occurs by this heating, and the chemical heat storage body granulated material in the reaction vessel 11 is chemically changed to an oxide. In addition, the temperature of the chemical heat storage material granule in the reaction vessel 11 is detected by a thermocouple 21 disposed in the reaction vessel 11.

(Procedure 4)
When the temperature of the chemical heat storage material granulated material in the reaction vessel 11 reaches the target temperature, the operation of the mantle heater 14 is stopped, and the chemical heat storage material granulated material in the reaction vessel 11 is naturally cooled. When the temperature of the chemical heat storage granule in the reaction vessel 11 is lowered to 80 ° C., the third valve 20 is closed and the first valve 18 is opened. Thereby, the space in the case 121 of the water vapor generator 12 communicates with the space in the reaction vessel 11 through the first pipe 15 and the second pipe 16. For this reason, the water vapor generated in the case 121 of the water vapor generator 12 is introduced into the reaction vessel 11. The introduction of water vapor into the reaction vessel 11 causes the chemical heat storage granule in the reaction vessel 11 to come into contact with the water vapor to start an exothermic reaction (hydration reaction). Thereby, a chemical heat storage body granulated material thermally radiates. At this time, the temperature (temperature increase temperature) of the chemical heat storage body granulated product is detected by the thermocouple 21. When the exothermic reaction is completed and the temperature of the chemical heat storage material granule starts to decrease, the procedure returns to the procedure 2 and the procedures 2 to 4 are repeated.

By repeating the above-described procedure, temperature measurement of a plurality of cycles is repeated for the chemical heat storage body granulated product according to each example. Here, temperature measurement of 10 cycles is repeatedly performed about the chemical heat storage body granulated material which concerns on each example. Further, the temperature difference between the temperature at the start of the exothermic reaction (80 ° C.) and the maximum temperature in each cycle is obtained. And the arithmetic mean value of the temperature difference calculated | required about each cycle was made into temperature rising temperature (DELTA) T about a chemical heat storage body granulated material. Thus, temperature rising temperature (DELTA) T was calculated | required about each of the chemical heat storage body granulated material which concerns on each example.

(Measurement of strength)
Crush the chemical heat storage material granulation according to each example one by one, and calculate the fracture load per unit area (unit: gf / mm ²⁾ from the fracture load at the time of crushing and the equivalent circle diameter of the crushed chemical heat storage material granulation. ) As the strength. The intensity | strength of 100 chemical heat storage body granulated materials was calculated | required about each example, and the arithmetic mean value of the intensity | strength of 100 chemical heat storage body granulated materials was computed. The calculated average value was defined as the strength of the chemical heat storage body granulated product according to each example. For this strength measurement, a fully automatic powder hardness tester BHT-500 manufactured by Seishin Enterprise Co., Ltd. was used.

(Measurement of reaction durability)
About each of the chemical heat storage body granulated material which concerns on each example, the temperature measurement of 1000 cycles was performed using the temperature rising apparatus 10 shown in FIG. And based on the following formula | equation, the decreasing rate P (%) of temperature rising temperature (DELTA) T was calculated | required. The obtained decrease rate P was used as an index of reaction durability.
P = − (ΔT _1-10 −ΔT _990-1000 ) / ΔT _1-10 × 100
In the above formula, ΔT _1-10 is an arithmetic average value of the temperature increase ΔT in the _{initial stage} (1st cycle to 10th cycle), and ΔT _990-1000 is an _increase in the final _phase (990th cycle to 1000th cycle). It is an arithmetic average value of the temperature ΔT.

Table 1 shows the results of measurement of circularity R, specific surface area, reaction rate, temperature rise temperature ΔT, strength, reaction durability (reduction rate P) for each example, constituent components at the time of hydration of chemical heat storage particles, coating It is shown together with the components and weight ratio (addition amount) of the membrane.

(Consideration of measurement results)
In the chemical heat storage granule according to Examples 1 to 13, the temperature rise ΔT is 100 ° C. or higher. Moreover, in the chemical heat storage body granulated material which concerns on Examples 1-13, the fall rate P of temperature rising temperature (DELTA) T showing reaction durability does not fall below -12%. In addition, when the absolute value of the fall rate P is small, even if it uses a chemical heat storage body granulated material over a long period of time, heat storage performance (heat storage density) does not fall so much. That is, when the absolute value of the decrease rate P is small, the reaction durability is high. Moreover, in the chemical heat storage body granulated material which concerns on Examples 1-13, all intensity | strength is 50 gf / mm < ² > or more. The specific surface area of the chemical thermal storage particles with chemical heat accumulator granules according to Examples 1 to 13 is 2 g / mm ² or more and 203 g / mm ² or less.

Moreover, each chemical heat storage body granulated material which concerns on Example 1, 3, 4, 5 is the same except that the density | concentrations of the binder liquid (polyvinyl alcohol aqueous solution) used in the core particle manufacturing process and the granulation process differ. It is manufactured through the process. Specifically speaking, the difference in the concentration of the binder liquid in each of the examples is the lowest (1 wt%) in the binder liquid used in Example 3, and the concentration of the binder liquid (5 wt in Example 1). %) Is the next lowest, the concentration of the binder liquid used in Example 4 (7 wt%) is the next lowest, and the concentration of the binder liquid used in Example 5 (9 wt%) is the highest. Further, the specific surface area of the chemical heat storage particles according to Example 3 having the lowest binder liquid concentration is 2 g / mm ² , and the specific surface area of the chemical heat storage particles according to Example 1 having the next lowest binder liquid concentration is 4 g / mm ^2. The specific surface area of the chemical heat storage particles according to Example 4 having the second lowest binder liquid concentration is 24 g / mm ² , and the specific surface area of the chemical heat storage particles according to Example 5 having the highest binder liquid concentration is 203 g / mm ^2. It is. From this, it can be seen that the higher the concentration of the binder liquid, the larger the specific surface area. The reason is considered as follows. That is, the binder used in the core particle production process and the granulation process enters the chemical heat storage particles during the production process of the chemical heat storage particles. The binder that has entered the chemical heat storage particles is finally removed. Then, the part in which the binder existed among the surfaces of the chemical heat storage particles becomes voids. Here, the higher the concentration of the binder liquid, the larger the amount of binder that gets into the chemical heat storage particles during the production process of the chemical heat storage particles, and the more voids are formed on the surface of the chemical heat storage particles. The more voids, the more complicated the surface shape of the chemical heat storage particles. Therefore, the higher the concentration of the binder liquid, the more complicated the surface shape of the chemical heat storage particles and the larger the specific surface area.

  Moreover, the reaction durability (decrease rate P = -23%) of the chemical heat storage material granulation according to Comparative Example 1 is the reaction durability (decrease rate P =) of the chemical heat storage material granulation according to Examples 1 to 13. -1 to -12%). Moreover, circularity R (0.75) of the chemical heat storage body granulated material which concerns on the comparative example 1 is smaller than circularity R (0.8 or more) of the chemical heat storage body granulated material which concerns on Examples 1-13. . From these, it can be seen that the smaller the circularity R, the lower the reaction durability, and the higher the circularity R, the higher the reaction durability. Moreover, in order to obtain high reaction durability such that the decrease rate P is −20% or more, the circularity R is 0.8 or more as in the chemical heat storage body granulated product according to Examples 1 to 13. It turns out that there is a need. In addition, since the reason why the reaction durability becomes higher as the circularity R is higher has been described above, the description thereof is omitted here.

Moreover, the chemical heat storage body granulated product according to Comparative Example 4 is not provided with a coating film, and thus the strength is as low as 20 gf / mm ² . On the other hand, the coating film which consists of silica particles is formed in the surface of the chemical heat storage particle with which the intensity | strength is as high as 50 gf / mm < ² >, and the chemical heat storage body granulated material which concerns on Examples 1-13. From this, according to the chemical heat storage body granulated material which concerns on Examples 1-13, it turns out that intensity | strength is raised by reinforcing a chemical heat storage particle with a coating film.

Moreover, the specific surface area of the chemical heat storage particles according to Comparative Example 2 is 0.5 g / mm ² and is relatively small. Therefore, sufficient reaction gas cannot be taken into the chemical heat storage particles during the exothermic reaction. Therefore, in Comparative Example 2, the reaction rate is as low as 41%, and the temperature increase temperature ΔT is also as low as 25 ° C. The temperature rise temperature ΔT represents the level of heat dissipation or heat recovery performance (heat storage performance) of the chemical heat storage granule. The higher the temperature rise temperature ΔT, the faster the heat release or heat recovery, and the temperature rise temperature ΔT. The smaller the value, the slower the heat dissipation or heat recovery. Therefore, the heat storage performance of the chemical heat storage body granulated product according to Comparative Example 2 having a small temperature increase temperature ΔT is low. On the other hand, the specific surface area of the chemical heat storage particles included in the chemical heat storage granule according to Examples 1 to 13 having a high reaction rate of 50% or more and a high temperature increase ΔT of 100 ° C. or more is 2 g / mm. ² or more. From this, it can be seen that the heat storage performance is sufficiently enhanced when the specific surface area of the chemical heat storage particles included in the chemical heat storage granule is 2 g / mm ² or more.

Moreover, the specific surface area of the chemical heat storage body granulated material which concerns on the comparative example 3 is as large as 351 g / mm < ² >. For this reason, a large amount of reaction gas enters the chemical heat storage particles during the exothermic reaction. Therefore, the reaction rate reaches 100%. When the reaction rate is 100%, the volume change (volume expansion) accompanying the reaction is large. Therefore, the contact load which arises between the chemical heat storage body granulated material which adjoins at the time of an exothermic reaction is large, Therefore Fine pulverization of a chemical heat storage material granulated material advances. Therefore, the reaction durability of the chemical heat storage material granulated product according to Comparative Example 3 is as low as 38%. In addition, when the specific surface area is too large, the strength decreases due to too many voids present inside the chemical heat storage particles. Therefore, the strength of the chemical heat storage material granulated product according to Comparative Example 3 is as low as 18 gf / mm ² . Moreover, since the pulverization is promoted also by the low strength, the reaction durability is also lowered.

On the other hand, the specific surface area of the chemical heat storage particles included in the chemical heat storage body granules according to Examples 1 to 13 having a high reaction durability of −12% or higher and a strength of 50 g / mm ² or higher is 203 g / mm. ² or less. When the specific surface area is 203 g / mm ² or less, the amount of the reaction gas entering the chemical heat storage particles can be appropriately suppressed. For this reason, a reaction rate can be restrained to less than 100%, and, thereby, the volume expansion amount of the chemical heat storage body granulation accompanying an exothermic reaction can be suppressed moderately. When the volume expansion amount is moderately suppressed, it is possible to suppress an increase in contact load that occurs between the adjacent chemical heat storage granule during the exothermic reaction. Therefore, pulverization of the chemical heat storage material granulated product is further suppressed, and as a result, the reaction durability can be further improved. Furthermore, when the specific surface area is 203 g / mm ² or less, a certain strength can be maintained. That is, the specific surface area of the chemical thermal storage particles, by adjusting the 2 g / mm ² or more and 203 g / mm ² in the range, while maintaining a constant intensity and reactive durability can be enhanced thermal storage properties.

From the above, the chemical heat storage medium granules according to Examples 1 to 13 are a roundness R is 0.8 or more, the specific surface area of the chemical thermal storage particles 2 g / mm ² or more and 203 g / mm ² or less In addition, since the coating film is formed on the surface of the chemical heat storage particles, it can be seen that the reaction durability, strength, and heat storage performance are all high. That is, according to this embodiment, it is possible to provide a chemical heat storage body granulated product that has high durability, strength, and storage performance.

  Moreover, the chemical heat storage particle | grains with which the chemical heat storage body granulated material which concerns on Examples 1-8 and 10-13 is equipped contains calcium, The chemical heat storage particle with which the chemical heat storage body granulated material which concerns on Example 9 is equipped contains magnesium. It can be seen that the heat storage performance is excellent even when any component is included.

  Moreover, the coating film | membrane with which the chemical heat storage body granulated material which concerns on Examples 1-5 and Examples 9-13 is equipped with a silica particle, and the coating film with which the chemical heat storage body granulated material which concerns on Example 6 is provided is an alumina particle. The coating film included in the chemical heat storage body granulated product according to Example 7 is configured with zirconia particles, and the coating film included in the chemical heat storage body granulated product according to Example 8 is configured with titania particles. It can be seen that the strength is high even when the coating film is composed of any of the above-described particles.

  Moreover, the weight ratio (addition amount) of the coating film with which the chemical heat storage material granulation according to Example 10 is provided is 0.5 wt%, and the weight ratio of the coating film with which the chemical heat storage material granulation according to Example 11 is provided. Is 1 wt%, the weight ratio of the coating film provided in the chemical heat storage material granulation according to Example 1 is 5 wt%, and the weight ratio of the coating film provided in the chemical heat storage material granulation according to Example 12 is 10 wt%. %, And the weight ratio of the coating film provided in the chemical heat storage material granulated product according to Example 13 is 20 wt%. The intensity | strength of the chemical heat storage body granulated material which concerns on these examples is high. Therefore, if the weight ratio of the coating film is within the above range, that is, if the weight ratio of the coating film is 0.5 wt% or more and 20 wt% or less, a chemical heat storage granule with sufficiently high strength is formed. Can do.

DESCRIPTION OF SYMBOLS 11 ... Reaction container, 12 ... Water vapor generator, 13 ... Vacuum pump, 14 ... Mantle heater, 15 ... First piping, 16 ... Second piping, 17 ... Third piping, 18 ... First valve, 19 ... Second valve 20 ... Third valve, 21 ... Thermocouple

Claims (4)

Chemical heat storage particles that are formed into particles by a material capable of storing chemical heat and have a specific surface area of 2 m ² / g or more and 203 m ² / g or less,
A porous coating film formed on the surface of the chemical heat storage particles,
A chemical heat storage granule having a circularity R defined by the following formula of 0.8 or more.
R = 4πS / L ²
S: Projected area of granulated product of chemical heat storage material L: Length of contour line of granulated product of chemical heat storage material In the chemical heat storage granule according to claim 1,
A chemical heat storage granulated product, wherein the chemical heat storage particles contain calcium or magnesium. In the chemical heat storage granule according to claim 1 or 2,
A chemical heat storage granule, wherein the coating film is formed of a compound containing at least one selected from the group consisting of silicon, titanium, aluminum, and zirconium. In the chemical heat storage granule according to claim 3,
A chemical heat storage granule, wherein the coating film is formed of at least one selected from the group consisting of silica particles, titania particles, alumina particles, zirconia particles, aluminum nitride particles, and silicon carbide particles.